org.apache.samoa.moa.classifiers.core.splitcriteria

Class InfoGainSplitCriterion

java.lang.Object

org.apache.samoa.moa.AbstractMOAObject

org.apache.samoa.moa.options.AbstractOptionHandler

org.apache.samoa.moa.classifiers.core.splitcriteria.InfoGainSplitCriterion

All Implemented Interfaces:

com.github.javacliparser.Configurable, Serializable, SplitCriterion, MOAObject, OptionHandler

Direct Known Subclasses:

InfoGainSplitCriterionMultilabel

public class InfoGainSplitCriterion
extends AbstractOptionHandler
implements SplitCriterion

Class for computing splitting criteria using information gain with respect to distributions of class values. The split criterion is used as a parameter on decision trees and decision stumps.

Version:

$Revision: 7 $

Author:

Richard Kirkby (rkirkby@cs.waikato.ac.nz)

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
com.github.javacliparser.FloatOption	minBranchFracOption

Constructor Summary

Constructors

Constructor and Description
InfoGainSplitCriterion()

Method Summary

Modifier and Type	Method and Description
static double	computeEntropy(double[] dist)
static double	computeEntropy(double[][] dists)
void	getDescription(StringBuilder sb, int indent) Returns a string representation of this object.
double	getMeritOfSplit(double[] preSplitDist, double[][] postSplitDists) Computes the merit of splitting for a given ditribution before the split and after it.
double	getRangeOfMerit(double[] preSplitDist) Computes the range of splitting merit
static int	numSubsetsGreaterThanFrac(double[][] distributions, double minFrac)

Methods inherited from class org.apache.samoa.moa.options.AbstractOptionHandler

copy, getCLICreationString, getOptions, getPurposeString, prepareForUse, prepareForUse

Methods inherited from class org.apache.samoa.moa.AbstractMOAObject

copy, measureByteSize, measureByteSize, toString

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface org.apache.samoa.moa.options.OptionHandler

copy, getCLICreationString, getOptions, getPurposeString, prepareForUse, prepareForUse

Methods inherited from interface org.apache.samoa.moa.MOAObject

measureByteSize

Field Detail

minBranchFracOption

public com.github.javacliparser.FloatOption minBranchFracOption

Constructor Detail

InfoGainSplitCriterion

public InfoGainSplitCriterion()

Method Detail

getMeritOfSplit

public double getMeritOfSplit(double[] preSplitDist,
                              double[][] postSplitDists)

Description copied from interface: SplitCriterion

Computes the merit of splitting for a given ditribution before the split and after it.

Specified by:

getMeritOfSplit in interface SplitCriterion

Parameters:

preSplitDist - the class distribution before the split

postSplitDists - the class distribution after the split

Returns:

value of the merit of splitting

getRangeOfMerit

public double getRangeOfMerit(double[] preSplitDist)

Description copied from interface: SplitCriterion

Computes the range of splitting merit

Specified by:

getRangeOfMerit in interface SplitCriterion

Parameters:

preSplitDist - the class distribution before the split

Returns:

value of the range of splitting merit

computeEntropy

public static double computeEntropy(double[] dist)

computeEntropy

public static double computeEntropy(double[][] dists)

numSubsetsGreaterThanFrac

public static int numSubsetsGreaterThanFrac(double[][] distributions,
                                            double minFrac)

getDescription

public void getDescription(StringBuilder sb,
                           int indent)

Description copied from interface: MOAObject

Returns a string representation of this object. Used in AbstractMOAObject.toString to give a string representation of the object.

Specified by:

getDescription in interface MOAObject

Parameters:

sb - the stringbuilder to add the description

indent - the number of characters to indent